1. Field of the Invention
The present invention relates to an endoscopic apparatus and, more particularly, to an endoscopic apparatus capable of imaging an internal portion of a living body by means of a narrow band light.
2. Description of the Related Art
Endoscopic apparatuses having an endoscope, a light source device and other components have been widely used in the field of medical treatment or the like. In particular, endoscopic apparatuses in the field of medical treatment are applied mainly to uses in which an operator or the like performs imaging or the like of an internal portion of a living body.
Instances of imaging with an endoscopic apparatus generally known in the field of medical treatment include normal imaging that is performed by irradiating a subject in a living body with white light, and that enables obtaining generally the same image of the subject as one observed with the naked eye, and imaging with a narrow band light (narrow band imaging (NBI)) that is performed by irradiating the subject with narrow band light having a band narrower than that of illumination light in the normal imaging, and that thereby enables obtaining an image in which blood vessels and other portions in a mucosal surface layer in a living body are emphasized in comparison with the normal imaging.
An endoscopic apparatus proposed in Japanese Patent Application Laid-Open Publication No. 2002-095635 is configured of a light source device provided with a filter having discrete spectral characteristics for outputting a narrow band illumination light, and an endoscope for picking up an image of a subject illuminated with the illumination light. The endoscopic system proposed in Japanese Patent Application Laid-Open Publication No. 2002-095635 has the above-described configuration and is therefore capable of narrow band imaging of the subject.